The visual perception of materials is a basic part of human vision, but is currently not well understood. People depend on material perception constantly in daily life. Examples are in navigation (Am I about to step on an icy patch?), eating (Is this cream cheese moldy?), mate selection (Does my date have healthy looking skin?), and medical diagnosis (Is this a suspicious looking mole?). Prior research in material perception has mainly used simple, controllable stimuli. This project will study a diverse range of naturalistic stimuli, such as occur in the real world. In order to do so, novel techniques that are quite different from those commonly used in material perception will be developed. New image databases will also be developed. In one set of experiments, subjects will see objects of a fixed shape made of different materials, and the researchers will assess the subjects'ability to judge and describe material qualities. In another set of experiments, subjects will view images from a finite set of categories, (for example, plastic, paper, cloth, or metal) and the researchers will measure the speed and accuracy of categorization. There is evidence that human observers can extract material information extremely rapidly, the experiments will quantify the course of this capability. In other experiments, subjects will see images that are degraded in various ways, which will elucidate the importance of various factors such as color, contrast, and detail in material perception. The project will provide a foundation for future work on material perception in the real world. An understanding of these basic issues would help in understanding some practical visual problems. For example, as people get older, their vision degrades, making it more difficult to detect slippery patches of floors or sidewalks. A science of material perception would help in developing recommendations on the lighting, layout, and materials used in sidewalks and corridors. In another example, when a physician is evaluating a patient in telemedicine (i.e., viewing the patient over a video link), different kinds of image degradation will lead to different difficulties in judging the appearance of, say, a wound, a rash, or a mole. A science of material perception could lead to improvements in video quality that are essential to the telemedicine setting. PUBLIC HEALTH RELEVANCE: The visual perception of materials is an essential visual capability. Degraded vision limits the ability to make basic judgments about the slipperiness of a sidewalk, the freshness of food, or the health of skin. Little is known about these capabilities, and the proposed research will establish some of the foundations needed for a theoretical and practical understanding of material perception.